Mushikago no Joumae.

A religious cult called Mushikago no Niwa that secretly developed hidden human potential existed in the past. However, one such person, whose potential was unleashed, rose in rebellion. After the cult was destroyed, the members dispersed and only the rumour of a vast fortune on the cult grounds is whispered in the underworld. Nanami is a go-between and trades information with people of the underworld. One day, he meets Kagoroku who happens to be there when he is in a tough spot in a secret deal. The two of them eventually team up to solve all sorts of issues. They get involved in a fight between the former Mushikago no Niwa members that went through human experiments and the people of the underworld over the assets and mystery of the cult.